Arc end tooth self-adaptive rounding and chamfering machining method based on on-machine measurement

Abstract

The invention discloses a circular arc end tooth self-adaptive rounding and chamfering processing method based on on-machine measurement, which obtains actual part measurement data through an on-line measurement means, can calculate the deviation between an actual model and a theoretical model according to an on-machine measurement result of a circular arc end tooth, and reconstructs an end tooth rounding and chamfering surface. And position and shape compensation is carried out according to the reconstructed tooth profile surface, and a tool path is automatically calculated to update a machining program, so that the machining precision of part machining is improved, self-adaptive rounding and chamfering of the end tooth are realized, the phenomenon of over-cutting or under-cutting of the machined rounding and chamfering caused by deviation between a theoretical workpiece and an actual workpiece during arc end tooth machining is solved, and the machining precision of the arc end tooth is improved. And the service life and the stability of the arc end tooth in actual use are influenced.

Description

Technical Field

[0001] The present invention relates to the technical field of arc end tooth machining, and more specifically, to an adaptive rounding and chamfering machining method for arc end teeth based on in-machine measurement. Background Art

[0002] The rotor of an aeroengine is in a working condition of high speed, high load, and high temperature. Therefore, its connecting mechanism not only needs to have sufficient strength and rigidity, but also ensure stable centering between various parts in various states. It also needs to ensure a simple structure, light weight, simple manufacturing, and convenient disassembly. With the continuous improvement of the performance requirements of aeroengines, higher requirements are also put forward for the connection methods between aeroengine rotors.

[0003] As a special structure form for the connection of turbine disks, the arc end tooth structure has the characteristics of strong load transmission capacity, high structural strength, high indexing accuracy and repeat positioning accuracy, self-centering, simple disassembly and maintenance, etc. Therefore, it is widely used in the compressor and turbine components of aeroengines. The arc end teeth are machined by a gear grinding machine, and the tooth profile structure is obtained by grinding the tooth blank with a formed grinding wheel. Therefore, high precision of the arc end teeth needs to be ensured. At the same time, there are sharp edges on the tooth profile after machining, and rounding and chamfering are required to avoid the influence of the sharp edges on the connection.

[0004] In the arc end tooth numerical control machining method based on machining precision index calibration disclosed in CN 101733482B, a machining strategy for calibrating machining precision and cutting parameters by introducing simulation analysis is directly used for the numerical control machining of the arc end tooth part. First, the theoretical meshing parameters of the full-size arc end tooth are solved, and then the numerical control machining tool path is directly generated based on the simulation analysis for calibrating machining precision and cutting amount. This patent integrates simulation analysis and numerical control machining technology by adopting a machining strategy for calibrating machining precision and cutting parameters, improving machining precision and machining efficiency. Although this patent constructs arc end teeth by giving a series of discrete radius pre-estimation values and using the positions of the predetermined discrete data points as the control rotation center. However, due to reasons such as tool wear and five-axis linkage non-linear errors during the machining process, after the actual end tooth machining is completed, there is a deviation between the actual shape of the part and the theoretical CAD model, and the theoretical program does not match the actual workpiece during actual machining. When rounding and chamfering the end teeth, over-cutting or under-cutting occurs in the actual program machining, which cannot guarantee the qualification rate and consistency, and affects the service life and stability of the arc end teeth in actual use. Summary of the Invention

[0005] The main technical problem to be solved by the present invention is to provide an adaptive rounding and chamfering machining method for arc end teeth based on in-machine measurement, aiming at the deficiency of over-cutting or under-cutting in the rounding and chamfering during the machining of arc end teeth in the prior art due to the deviation between the theory and the actual workpiece.

[0006] The object of the present invention is achieved by the following technical solutions:

[0007] An adaptive rounding and chamfering machining method for circular-arc end teeth based on in-machine measurement, the steps include:

[0008] S1. Clamp the machined part and construct the initial coordinate system;

[0009] S2. Measure the coordinates of the part, and perform coordinate system transformation according to the measurement results, and correct the initial part coordinate system to obtain the corrected coordinate system;

[0010] S3. Calculate the origin position of the part in the corrected coordinate system, measure the position deviations in the axial and circumferential directions of the part in the corrected coordinate system, and verify the corrected coordinate system according to the position deviations;

[0011] S4. Establish the end tooth feature, construct the end tooth feature surface, and measure the end tooth angular orientation, inner and outer circular surfaces and tooth profile, and reconstruct the tooth profile according to the obtained measurement results;

[0012] S41. Select measurement points on both symmetric sides of the end tooth feature surface, make a rotation in the Z-axis direction, and confirm the end tooth angular position;

[0013] S42. Measure the inner and outer circular surfaces of the machined external tooth profile respectively, uniformly select multiple measurement points on the inner and outer circular surfaces, make a translation in the XOY plane, obtain the deviation value in the diameter direction, and perform tool path adaptive compensation in the diameter direction according to the deviation value;

[0014] S43. Measure the tooth profile, fit the best actual machined tooth profile, and the measured data is used for tool path adaptive compensation;

[0015] Among them, the tool path adaptive compensation in S42 and S43 includes:

[0016] (1) According to multiple measurement points collected on the machining surface, interpolate towards the middle area of the machining surface in a triangular meshing manner, so that all adaptive areas on the machining surface are covered by triangular meshes, and approximately obtain the shape error values of all tool positions in the adaptive area;

[0017] (2) Then perform error compensation on the tool positions along the normal direction of the surface where they are located, to achieve adaptive correction compensation of the shape errors of all tool positions;

[0018] (3) Calculate the average error of all tool positions on this section of the tool path, and then perform overall shape compensation on the entire tool path.

[0019] S5. Input the rounding and chamfering parameters, and perform adaptive end tooth machining with correction according to the measurement results.

[0020] Furthermore, step S1 includes:

[0021] S11. Take multiple measurement points circumferentially along the end face of the arc-shaped end teeth, match the end face of the arc-shaped end teeth of the turbine disk, establish an XYZ coordinate system, make the plane of the arc-shaped end teeth parallel to the machining XOY plane, and complete the leveling;

[0022] S12. Take multiple measurement points on the end face of the arc-shaped end teeth, only make an offset in the Z direction, set the Z origin of the part on the end face of the end teeth, and match ZO;

[0023] S13. Select the machining reference circle of the arc-shaped end teeth as the measurement object, evenly take multiple measurement points on the machining reference circle, only make a translation in the XOY plane, and match XO and YO;

[0024] S15. Take measurement points symmetrically on both the left and right sides of the end teeth, only make a rotation in the Z-axis direction, and confirm the angular position of the end teeth.

[0025] Furthermore, the coordinates in step S2 include the point coordinates measured on the end face, the point coordinates measured on the circumference, and the point coordinates measured on the tooth surfaces on both sides of the end teeth.

[0026] The calculation of the corrected coordinate system in step S2 includes:

[0027] S21. Assume the tool position point P tip and the tool axis vector V tov in the original tool path, and their homogeneous coordinates are respectively expressed as:

[0028]

[0029] S22. Assume that the inverse transformation A -1 of the rigid body transformation A from the current actual clamping position to the theoretical clamping position is calculated, and its homogeneous coordinate representation is:

[0030]

[0031] S22. The calculation method of the tool position point P′ tip after position adaptive compensation is: P′ tip = A -1 ·P tip , and the calculation method of the same tool axis vector V′ tov is: V′ tov = A -1 ·V tov , and substitute it into the homogeneous matrix for calculation:

[0032]

[0033] Furthermore, since the translation transformation does not change the magnitude and direction of the vector, only the rotation part of the rigid body transformation is considered when correcting the tool axis vector V tov .

[0034] Further, the verification in step S3 includes:

[0035] Measure the points on the end face of the arc-shaped end teeth, the reference circular face, and both sides of the end teeth respectively, obtain the axial and circumferential position deviations of the part in the corrected coordinate system, and perform the measurement in the corrected coordinate system. If the obtained measurement result is consistent with the expectation, it means that the corrected coordinate system is correct.

[0036] Further, constructing the end tooth feature surface in step S41 includes the left tooth surface, the right tooth surface, the inner circular surface, the outer circular surface, the tooth top surface, the left mountain-shaped bottom, and the right mountain-shaped bottom features.

[0037] Further, step S41 also includes the verification of the angular position of the end teeth.

[0038] Further, the rounding and chamfering parameters in step S5 include the total number of teeth of the gear, the machining fillet radius, the root transition fillet radius, and the machining position.

[0039] An adaptive rounding and chamfering machining device for arc-shaped end teeth with in-machine measurement, comprising a measurement equipment system, a workbench, a servo system, a CNC numerical control system, a probe, and a computer. The measurement equipment system and the workbench are connected to the servo system. The equipment measurement system is also connected to the probe. The servo system and the probe are bidirectionally connected to the CNC numerical control system. The CNC numerical control system is connected to the computer. The CNC numerical control system transmits the measurement data to the computer. The computer generates a measurement program to the CNC numerical control system. The CNC numerical control system then transmits the program instructions to the probe and the servo system. The servo system controls the position transformation of the measurement equipment and the workbench to complete the machining of the arc-shaped end teeth.

[0040] Compared with the prior art, the beneficial effects are:

[0041] The present invention obtains the actual part measurement data through on-line measurement means, can calculate the deviation between the actual model and the theoretical model according to the in-machine measurement result of the arc-shaped end teeth, reconstruct the rounding and chamfering surface of the end teeth, and perform position and shape compensation according to the reconstructed tooth profile surface, automatically calculate the tool path and update the machining program, improving the machining accuracy of the part and realizing the adaptive rounding and chamfering of the end teeth.

[0042] The present invention is based on point-based and line-based adaptive compensation. First, the shape error values of all tool points in the adaptive region are approximately obtained through several measured points, and the tool points are compensated according to the tool points to achieve the adaptive correction and compensation of the tool points. On this basis, the average error of all tool points on this section of the tool path is calculated, and then the overall shape compensation of the entire tool path is performed to ensure the smoothness of the tool path and the surface finish of the machined surface. Description of the Drawings

[0043] Figure 1Schematic diagram of the process for constructing the initial coordinate system.

[0044] Among them, a is for leveling, b is for ZO matching, c is for XO and YO matching, and d is for confirming the angular position of the end teeth.

[0045] Figure 2 Schematic diagram of the process for reconstructing the tooth profile.

[0046] Among them, a is for matching the angular position of the end teeth, b is for verifying the angular position of the end teeth, c is for measuring the inner circular surface, d is for measuring the tooth profile surface, e is for measuring the tooth angle, f is for measuring the inner circular surface, and g is for measuring the tooth profile result.

[0047] Figure 3 Schematic diagram of the corresponding positions of each feature of the circular arc end teeth.

[0048] Figure 4 Schematic diagram of shape adaptive compensation based on points and lines;

[0049] Figure 5 Schematic diagram of adaptive error compensation;

[0050] Figure 6 Comparison diagram of the blue theoretical tool path and the red adaptive tool path.

[0051] Figure 7 Schematic diagram showing the machining effect of the part. Detailed implementation method

[0052] The following further explains and clarifies in combination with embodiments, but the specific embodiments do not have any form of limitation on the present invention.

[0053] Embodiment 1

[0054] This embodiment provides an adaptive rounding and chamfering machining method for circular arc end teeth based on in-machine measurement. The steps include:

[0055] S1. Clamp the machined part and construct the initial coordinate system;

[0056] S11. Take 10 measurement points circumferentially along the end face of the circular arc end teeth, establish the XYZ coordinate system, match the end face of the circular arc end teeth of the turbine disk, and make the end face plane of the circular arc end teeth parallel to the machining XOY plane to complete leveling.

[0057] S12. Take 4 measurement points on the end face of the circular arc end teeth, only make an offset in the Z direction, set the Z origin of the part on the end face of the end teeth, and match ZO.

[0058] S13. Select the machining reference circle of the circular arc end teeth as the measurement object, evenly take 4 measurement points on the machining reference circle, only make a translation in the XOY plane, match XO and YO, and complete the matching of the origin position of the machining coordinate system of the part, that is, the alignment of the part rotation center Y0 and X0.

[0059] S15. Symmetrically take 4 measurement points on the left and right sides of the first end tooth (the first end tooth to be machined), and only rotate in the Z-axis direction to confirm the angular position of the end tooth, that is, the tooth profile center line of the first end tooth.

[0060] S2. Measure the point coordinates measured on the end face of the part, the point coordinates measured on the circumference, and the point coordinates measured on the tooth surfaces on both sides of the end tooth, and perform coordinate transformation according to the measurement results to correct the initial coordinate system and obtain the corrected coordinate system;

[0061] When clamping the part on the machine tool, due to the error of manual operation or the rough datum error of the workpiece itself, there is a clamping position error that can be represented by a rigid body transformation between the current actual clamping position of the workpiece and the desired theoretical clamping position, and obtain this rigid body transformation T A , After A, the method for correcting and compensating the original machining tool path is essentially to perform coordinate transformation on the tool point and the tool axis vector, specifically as follows:

[0062] S21. Assume that the tool point P tip and the tool axis vector V tov in the original tool path are respectively represented in homogeneous coordinates as:

[0063]

[0064] S22. Assume that the inverse transformation A -1 of the rigid body transformation A calculated from the current actual clamping position to the theoretical clamping position is represented in homogeneous coordinates as:

[0065]

[0066] S22. The calculation method of the tool point P' tip after position adaptive compensation is: P' tip = A -1 · P tip , and the calculation method of the same tool axis vector V' tov is: V' tov = A -1 · V tov , and substitute it into the homogeneous matrix for calculation:

[0067]

[0068] Since the translation transformation does not change the magnitude and direction of the vector, only the rotation part of the rigid body transformation is considered when correcting the tool axis vector V tov .

[0069] S3. Calculate the accurate origin position of the part in the corrected coordinate system, and check the axial and circumferential errors of the part according to this origin position. Specifically, for the measurement and calibration of Z0, X0 / Y0, and angular orientation, measure the points on the end face of the arc-shaped end teeth, the reference circular surface, and the left and right sides of the first tooth respectively. Measure the axial and circumferential position deviations of the part in the corrected coordinate system, and then verify the correctness of the corrected coordinate system according to the deviations of the measurement results. If the deviations measured in the corrected coordinate system are within the threshold, the obtained measurement results are consistent with the expectations, indicating that the corrected coordinate system is correct.

[0070] S4. Establish the arc-shaped end tooth feature. Under the arc-shaped end tooth feature, successively select the feature surfaces on the model, and correspondingly add the left tooth surface, right tooth surface, inner circular surface, outer circular surface, tooth top surface, left of the mountain-shaped bottom, and right of the mountain-shaped bottom features to construct the end tooth feature surface, that is, the first end tooth.

[0071] S5. Measure the angular orientation of the end teeth, the inner and outer circular surfaces, and the tooth profile, and reconstruct the tooth profile according to the obtained measurement results.

[0072] S51. Symmetrically take 4 measurement points on the left and right sides of the first end tooth, and only rotate in the Z-axis direction to align the tooth profile center line of the first end tooth. Confirm the angular positions of multiple teeth to complete the verification of the angular positions of the end teeth.

[0073] S52. Measure the inner and outer circular surfaces of the machined external tooth profile respectively. Uniformly select multiple measurement points on the inner and outer circular surfaces. Measure the outer circle when machining the external tooth profile and measure the inner circle when machining the internal tooth profile. Make a translation in the XOY plane to obtain the deviation value in the diameter direction. Use this deviation value for tool path adaptive compensation, including:

[0074] (1) According to the multiple measurement points collected on the machining surface, interpolate to the middle area of the machining surface in a triangular meshing manner, so that all adaptive areas on the machining surface are covered by triangular meshes, and thus the shape error values of all tool positions in the adaptive area can be approximately obtained.

[0075] (2) Then compensate the error of the tool position along the normal direction of the surface where it is located, so as to realize the adaptive correction and compensation of the shape error of all tool positions.

[0076] (3) Since the above-mentioned point-based shape error compensation may largely damage the smoothness of the original tool path, resulting in an uneven and non-smooth machining surface, a line-based method is adopted, that is, a complete tool path segment. First, calculate the average error of all tool positions of this tool path segment, and then perform an overall shape compensation on the entire tool path to ensure the smoothness of the tool path and the surface finish of the machining surface.

[0077] S53. Select the machined tooth profile of the arc end teeth as the measurement object for measurement. When machining the external tooth profile, select the external tooth profile; when machining the internal tooth profile, select the internal tooth profile. Similarly, fit the best actual machined tooth profile, and the measured data is used for tool path adaptive compensation.

[0078] S6. Input the total number of gear teeth, machining fillet radius, root transition fillet radius, and machining position, and perform adaptive end tooth machining with corrections based on the measurement results.

[0079] Example 2

[0080] This embodiment provides an in-machine measurement arc end tooth adaptive rounding and chamfering machining device, which includes a measurement equipment system, a workbench, a servo system, a CNC numerical control system, a probe, and a computer. The measurement equipment system and the workbench are connected to the servo system, and the equipment measurement system is also connected to the probe. The servo system, the probe, and the CNC numerical control system are bidirectionally connected. The CNC numerical control system is connected to the software on the computer. The CNC numerical control system transmits the measurement data to the machining software on the computer. The software generates a measurement program to the CNC numerical control system according to the method described in Example 1. The CNC numerical control system then transmits the program instructions to the probe and the servo system, and the servo system controls the position transformation of the measurement equipment and the workbench to complete the machining of the arc end teeth.

[0081] Example 3

[0082] Taking the arc end teeth of a certain type of turbine disk as an example in this embodiment, the requirements for end tooth rounding and chamfering are 0.2 ± 0.1 mm. The total number of input gear teeth is 20, the machining fillet radius is 0.2 mm, the root transition fillet radius is 1.9 mm, and the machining position is the internal circular tooth profile. Figure 4 It can be seen that the adaptive tool path of the method of the present invention corrects the theoretical tool path. The test machining time is shown in Table 1 below:

[0083] Serial number Event Time 1 Quick clamping and alignment 4 min 12 s 2 Verification 2 min 3 External gear adaptive planning group 4 min 10 s 4 External gear machining group 1 41s 5 External gear machining group 5 58s 6 Internal gear adaptive planning group 4 min 5 s 7 Internal gear machining group 1 45S 8 Internal gear machining group 5 1 min 25 s

[0084] As Figure 5 shown in the finished part, the arc end tooth connector machined by the present invention fits perfectly.

[0085] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. Adaptive rounding and chamfering machining method for circular arc end teeth based on in-machine measurement, characterized in that the steps Including: S1. Clamp the machined part and construct the initial coordinate system; S2. Measure the coordinates of the part, perform coordinate system transformation according to the measurement results, correct the initial part coordinate system, and obtain the corrected coordinate system; S3. Calculate the origin position of the part in the corrected coordinate system, measure the position deviations in the axial and circumferential directions of the part in the corrected coordinate system, and verify the corrected coordinate system according to the position deviations; S4. Establish the end tooth feature, construct the end tooth feature surface, measure the end tooth angular orientation, inner and outer circular surfaces, and tooth profile, and reconstruct the tooth profile according to the obtained measurement results; S41. Select measurement points on both symmetric sides of the end tooth feature surface, perform rotation in the Z-axis direction, and confirm the end tooth angular position; S42. Measure the inner and outer circular surfaces of the machined external tooth profile respectively, evenly select multiple measurement points on the inner and outer circular surfaces, perform translation in the XOY plane, obtain the deviation value in the diameter direction, and perform adaptive compensation on the tool path in the diameter direction according to the deviation value; S43. Measure the tooth profile, fit the best actual machined tooth profile, and the measured data is used for tool path adaptive compensation; Among them, the tool path adaptive compensation in S42 and S43 includes: (1) According to multiple measurement points collected on the machining surface, interpolate towards the middle area of the machining surface in a triangular meshing manner, so that all adaptive areas on the machining surface are covered by triangular meshes, and approximately obtain the shape error values of all tool positions in the adaptive area; (2) Then perform error compensation on the tool positions along the surface normal direction of the surface where they are located, and realize adaptive correction compensation of the shape errors of all tool positions; (3) Calculate the average error of all tool positions on this section of the tool path, and then perform overall shape compensation on the entire tool path. S5. Input the parameters for rounding and chamfering, and perform adaptive end tooth machining with correction according to the measurement results.

2. The adaptive rounding and chamfering machining method for circular arc end teeth based on in-machine measurement according to claim 1, wherein, Step S1 includes: S11. Take multiple measurement points circumferentially along the end face of the arc end tooth, match the end face of the arc end tooth of the turbine disk, establish the XYZ coordinate system, make the end face plane of the arc end tooth parallel to the machining XOY plane, and complete leveling; S12. Take multiple measurement points on the end face of the arc end tooth, only perform offset in the Z direction, set the Z origin of the part on the end face of the end tooth, and match ZO; S13. Select the machining reference circle of the arc end tooth as the measurement object, evenly take multiple measurement points on the machining reference circle, only perform translation in the XOY plane, and match XO and YO; S15. Take measurement points symmetrically on the left and right sides of the end tooth, only perform rotation in the Z-axis direction, and confirm the end tooth angular position.

3. The arc-end gear self-adaptive rounding and chamfering processing method based on in-machine measurement according to claim 1, characterized in that The coordinates in step S2 include the point coordinates measured on the end face, the point coordinates measured on the circumference, and the point coordinates measured on the tooth surfaces on both sides of the end tooth.

4. The arc-end gear adaptive rounding and chamfering processing method based on in-machine measurement according to claim 1, wherein The calculation of the corrected coordinate system in step S2 includes: S21. Assume the cutter location point P in the original tool path tip and the cutter axis vector V tov are respectively represented in homogeneous coordinates as follows: S22. Assume that the homogeneous coordinate representation of the inverse transformation A of the rigid body transformation A from the current actual clamping position to the theoretical clamping position is obtained by calculation as follows: -1 is as follows: The calculation method of the cutter location point P' tip after position adaptive compensation is: P' tip = A -1 ·P tip , and the calculation method of the same cutter axis vector V' tov is: V' tov = A -1 ·V tov , and substitute it into the homogeneous matrix for calculation:

5. The arc-end-tooth adaptive rounding and chamfering processing method based on in-machine measurement according to claim 4, wherein, Tool axis vector V tov Only consider the rotational part of the rigid body transformation during correction.

6. The adaptive chamfering and rounding machining method for arc-shaped end teeth based on in-machine measurement according to claim 1, wherein The verification in step S3 includes: Measure the points on the end face of the arc end tooth, the reference circle surface, and both sides of the end tooth respectively, obtain the axial and circumferential position deviations of the part in the corrected coordinate system. If the deviations are within the threshold range, the corrected coordinate system is correct.

7. The adaptive rounding and chamfering machining method for arc-end teeth based on in-machine measurement according to claim 1, characterized in that, The construction of the end tooth feature surface in step S41 includes the left tooth surface, right tooth surface, inner circular surface, outer circular surface, tooth top surface, left mountain-shaped bottom, and right mountain-shaped bottom features.

8. The adaptive rounding and chamfering processing method for circular arc end teeth based on in-machine measurement according to claim 1, characterized in that Step S41 also includes the verification of the end tooth angular position.

9. The adaptive rounding and chamfering machining method for arc-end teeth based on in-machine measurement according to claim 1, wherein The rounding and chamfering parameters in step S5 include the total number of gear teeth, the machining fillet radius, the root fillet radius, and the machining position.

10. An adaptive rounding and chamfering machining device for arc-end teeth in on-machine measurement, characterized in that, It includes a measuring equipment system, a workbench, a servo system, a CNC numerical control system, a probe, and a computer. The measuring equipment system and the workbench are connected to the servo system. The equipment measuring system is also connected to the probe. The servo system and the probe are bidirectionally connected to the CNC numerical control system. The CNC numerical control system is connected to the computer. The CNC numerical control system transmits measurement data to the computer. The computer generates a measurement program and sends it to the CNC numerical control system. The CNC numerical control system then transmits program instructions to the servo system and the probe. The servo system controls the position transformation of the measuring equipment and the workbench to complete the machining of the circular arc end teeth.

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